多种方法测定化肥中总镁含量的比较研究

Comparison and study on determination of magnesium content in chemical fertilizers by multiple methods

研究建立了微波消解-电感耦合等离子体发射光谱法(ICP-OES法)以及原子吸收分光光度法(AAS法)测定化肥中镁元素含量的检测方法。分别使用新方法和国家标准GB/T 19203—2003中的传统方法,对2种复合肥料标准物质以及15种不同产地、不同镁源、不同镁含量的化肥样品进行测定。t检验结果表明微波消解法与GB/T 19203—2003中硝酸-高氯酸电热板消解法的提取结果无显著性差异;ICP-OES法、AAS法和GB/T 19203—2003中容量法的测定结果无显著性差异。ICP-OES法与AAS法的回收率、精密度均优于容量法。微波消解-ICP-OES法的标准物质回收率分别为110%、108%,6次平行测定的相对标准偏差为0.80%。微波消解-AAS法的标准物质回收率分别为109%、108%,6次平行测定的相对标准偏差为1.29%。与AAS法相比,ICP-OES法的精密度和标准曲线决定系数均更优,标准曲线线性范围更宽,且在实验过程中更加简便、环保,更适用于化肥样品的分析测定。

New methods for the determination of magnesium in fertilizer by microwave digestion using inductively coupled plasma optical emission spectrometry(ICP-OES method)and atomic absorption spectrometry(AAS method)were established.The results of the new methods and the method in the national standard GB/T 19203-2003 were studied by t-test.Two compound fertilizer standard materials and 15 fertilizer samples from different regions,different magnesium sources and different magnesium contents were determined.The t-test results showed that there was no significant difference in the extraction results between the microwave digestion method and the nitric acid-perchloric acid electric heating plate digestion method in GB/T 19203-2003;there was no significant difference in the measurement results among the ICP-OES method,AAS method and the volumetric method in GB/T 19203-2003.The recovery rate and precision of ICP-OES method and AAS method were superior to those of the volumetric method.For microwave digestion-ICP-OES method,the standard material recovery rates were 110%and 108%,respectively,and the relative standard deviation of 6 parallel determinations was 0.80%.For microwave digestion-AAS method,the standard material recovery rates were 109%and 108%,respectively,and the relative standard deviation of 6 parallel determinations was 1.29%.Compared with AAS method,the ICP-OES method had better precision and standard curve determination coefficient,wider linear range of the standard curve,and was more convenient and environmentally friendly in the experimental process,which made it more suitable for fertilizer samples.